Evaluation of time to shrinkage-induced crack initiation in OPC and slag cement matrices incorporating circulating fluidized bed combustion bottom ash

Abstract

The effect of bottom ash produced from circulating fluidized bed combustion (CFBC) on the shrinkage-induced cracking potential of ordinary Portland cement (OPC) and slag cement mixtures were investigated by evaluating the time to crack initiation, predicted by comparing tensile strength obtained from direct tensile tests with shrinkage-induced stress obtained from shrinkage strain and elastic modulus results. Although replacing OPC and slag cement amounts with CFBC bottom ash delayed cracking times due to its shrinkage compensation, the effect varied with the drying condition. Therefore, for effective application of CFBC ash in cement mixtures, boundary conditions affecting drying rates need careful consideration.